Their substantial meals could disrupt the fishing industry. 

By Elisabeth Sherman
Updated July 12, 2017
Humpback whales Alaska salmon hatcheries
Credit: John E Marriott / Getty Images 

Alaska’s humpback whales have found a way to use human encroachment on their ocean homes to their advantage: The clever cetaceans are sneaking into salmon hatcheries in Southeastern Alaska and helping themselves to the fish. But their clever tactics may soon wreak havoc on the state’s fishing industry, according to a report from the New Scientist.

Salmon hatcheries aren’t fish farms – rather, they’re set up to help support the wild salmon population in Alaskan waters. Once the salmon are mature (they’re at bred in captivity for around 18 months, a crucial stage during which many salmon die in the wild), they’re released into the ocean, increasing the overall salmon available to catch and preventing overfishing of the wild salmon.

It was a scientist at the University of Alaska Fairbanks named Ellen Chenoweth who first noticed the whales lingering near the hatcheries, strange behavior for an animal that usually feeds on krill far out to see where it’s difficult to observe them.

A humpback whale is typically forty feet long. When the salmon are released from the hatchery they're about the size of a human finger, according to Chenoweth. That means that these whales aren’t just stealing a handful of fish – they’re swallowing whole schools of the salmon at a time as they stream out of the hatcheries.

Chenoweth and team of researchers observed the whales for five years, from 2010 to 2015, and found that pillaging Alaska’s salmon reserves isn’t an essential feeding strategy for the survival of the humpback population overall. But for the small number of migrant humpback whales that discovered the practice, it’s a necessity.

“For the individuals that appear to specialize there, it is part of a seasonal feeding strategy and, in some cases, they return year after year,” Chenoweth told the New Scientist.

The ongoing decrease in the population could put extra pressure on the Alaska Salmon population – not yet an endangered species – disrupting the fragile relationship between the fisherman and their wild salmon catch. No new regulations concerning the amount of wild salmon they're allowed to catch have had to be instituted because of competition from the whales, but if Alaska's fishery community doesn't find a way to control what the whales take, Alaska's wild salmon may start to appear less (and cost more) at your local fish market.